<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>边框的练习</title>
    <style>
        /* 请给一个 200*200 的盒子，设置上边框为红色，其余边框为蓝色 */
        div {
            width: 200px;
            height: 200px;
            /* border-top: 1px solid red;
            border-bottom: 1px solid blue;
            border-left: 1px solid blue;
            border-right: 1px solid blue; */
            /* border包含四条边 */
            border: 1px solid blue;
            /* 层叠性 只是层叠了 上边框啊 */
            border-top: 1px solid red;
        }
    </style>
</head>
<body>
    <div></div>
</body>
</html>